1. Technical Field
The present invention relates to a picture display device and a picture display method that allow a plurality of computer devices to be connected, display screens thereof to be displayed on one screen, and the connected computer devices connected to be controlled by a common input device.
2. Background Art
Conventional computer devices are connected to an external monitor device and input devices such as a keyboard and a mouse. A user operates the input devices corresponding to a display on the monitor device so as to cause application software to perform a data process or the like.
Depending on a desired process and user's requirement, a plurality of computer devices may be activated and operated in parallel. In this case, from a viewpoint of the installation space of the monitor device and so forth, it is preferred to connect a plurality of computer devices to one monitor device.
FIG. 1 shows an example of which two computer devices 501A and 501B are connected to one monitor device 500 according to related art. In the following description, it is assumed that the computer devices are personal computers. The monitor device 500 can input two channels of video signals. A video signal 502A that is output from the personal computer main body 501A is input to a first video input terminal (not shown) of the monitor device. Likewise, a video signal 502B that is output from the personal computer main body 501B is input to a second video input terminal (not shown) of the monitor device 500.
A display portion 507 of the monitor device 500 displays contents corresponding to the video signals that are input from the first and second video input terminals. The monitor device 500 has an operation switch 505 on its front panel. For example, by operating the operation switch 505, an OSD (On Screen Display) screen 506 that represents settings of the monitor device 500 can be displayed in a predetermined area of the display portion 507. In addition, by operating the operation switch 505 in a predetermined manner, setting values of the monitor device 500 (for example, contrast, brightness, hue, and so forth) can be changed. Corresponding to the changed values, the display picture quality of the monitor device 500 are changed. In addition, a display of the OSD screen 506 is updated.
As input devices that allow a user's command to be input to the personal computer main body 501A, a keyboard 503A and a mouse 504A are connected thereto. The keyboard 503A transmits input key information to the personal computer main body 501A. The mouse 504A transmits the movement amounts in the (X, Y) directions of the mouse 504A and button operation information thereof to the personal computer main body 501A.
For example, the personal computer main body 501A converts the mouse movement amounts supplied from the mouse 504A into coordinates on the display portion 507 of the monitor device 500 so as to generate a video signal for displaying a cursor on the coordinates. The video signal for displaying the cursor is superimposed with the video signal 502A. The superimposed signal is supplied to the monitor device 500. As a result, the monitor device 500 displays a cursor 508.
Likewise, a keyboard 503B and a mouse 504B are connected to the personal computer main body 501B. Key information, mouse movement amounts, and button operation information are transmitted to the personal computer main body 501B. In the same manner as the personal computer main body 501A, the cursor 508 is displayed.
In the related art shown in FIG. 1, the video signal is statically switched between the video signal 502A of the personal computer main body 501A and the video signal 502B of the personal computer main body 501B by operating for example the operation switch 505.
FIG. 2 shows an example of the structure of the above-described monitor device 500. The video signal 502A that is output from the personal computer main body 501A and the video signal 502B that is output from the personal computer main body 501B are input to a first input terminal and a second input terminal of a video switch 512. The video switch 512 is controlled by a CPU 511 (that will be described later) so as to select one of the video signals that are input to the first input terminal and the second input terminal. The selected video signal is output from the video switch 512 and supplied to a first input terminal of a video mix circuit 514.
The monitor device 500 has the above-mentioned CPU 511. A signal corresponding to the operation of the operation switch 505 is supplied to the CPU 511. When the operation of the operation switch 505 represents the switching between the personal computer main body 501A and the personal computer main body 501B, a control signal that causes an input to be switched is supplied from the CPU 511 to the video switch 512.
When the operation of the operation switch 505 represents the displaying of the OSD screen 506, a command that causes the OSD screen 506 to be displayed is supplied from the CPU 511 to a character generator 25, 513. The character generator 513 generates a video signal for displaying the OSD screen 506 corresponding to the supplied command. The generated video signal is for example RGB signals. The video signal is supplied to a second input terminal of the video mix circuit 514.
The video mix circuit 514 switches the video signals supplied to the first and second input terminals at predetermined timings so that the OSD screen 506 is displayed at a predetermined area of the display portion 507. A video signal that is output from the video mix circuit 514 is supplied to a picture display device 516 composed of for example a CRT (Cathode Ray Tube) or an LCD (Liquid Crystal Display) and a corresponding drive circuit through a display control circuit 515.
The picture display device 516 causes the display portion 507 to display a picture corresponding to the frequency and resolution of the supplied video signal. For example, the picture display device 516 detects a horizontal synchronous signal and a vertical synchronous signal contained in the supplied video signal so as to obtain the horizontal frequency and vertical frequency.
When the settings of the monitor device 500 are changed by an operation of the operation switch 505, a control signal corresponding to the changed settings is supplied form the CPU 511 to the display control circuit 515. Corresponding to the control signal the video signal supplied to the display control circuit 515 is processed so as to adjust the display picture quality and so forth of the picture display device 516.
Since the computer devices 501A and 501B are connected to the monitor device 500 in such a manner, when the user operates the operation switch 505 in a predetermined manner, the personal computer main bodies 501A and 501B can be switchably operated. When the personal computer main body 501A has been selected, the user can operate it using the mouse 504A and the keyboard 503A while observing the display of the monitor device 500. Likewise, when the personal computer main body 501B has been selected, the user can operate it using the mouse 504B and the keyboard 503B while observing the display of the monitor device 500.
In addition, as shown in FIG. 3, when a plurality of personal computer main bodies 501A and 501B connected to the monitor device 500 are connected through a network 520, a data communication can be performed between the personal computer main bodies 501A and 501B. For example, a file can be transferred from the personal computer main body 50A to the personal computer main body 501B through the network 520.
Conventionally, even if a plurality of computer devices are connectable to one monitor device, the video switch that switches video signals of the plurality of computer devices that are connected is static as was described above. In addition, the frequencies of the video signals that are input from the plurality of computer devices are different and asynchronous. Thus, there is a problem of which video signals of a plurality of computer devices cannot be displayed on one monitor device at a time.
In other words, conventionally, to display video signals of for example two computer devices at a time, it is inevitable to use two monitor devices corresponding to the computer devices.
In addition, conventionally, to operate a plurality of computer devices, a corresponding number of sets of input devices such as keyboards and mice are required. Thus, from view points of installation space and operability, the conventional method is not effective.
In addition, the signal formats of video signals supplied from a plurality of computer devices connected to one monitor device are subject to be different and asynchronous. In such a case, in particular, when the monitor device 500 uses a CRT as a picture display device, to switch a plurality of video signals, it takes a time to determine the system of the supplied video signals. Thus, conventionally, a plurality of video signals cannot be quickly switched.
In addition, even if two personal computers 501A and 501B are connected to the monitor device 500, since the monitor device 500 can display only a video signal supplied from only one personal computer, the user should operate the operation switch 505 so as to manually select one of the personal computers 501A and 501B. Thus, even if the personal computer main body 501A and the personal computer main body 501B are connected through the network 520 as shown in FIG. 3, when the user tries to operate a file between the two personal computers 501A and 501B, the operation procedure becomes troublesome and takes a long time to switch the two personal computers. Consequently, the operability becomes low and the operation becomes inconvenient.
Depending on the OS (Operating System) for use, to operate a file between two different personal computers, it is necessary to exchange data therebetween through a common folder that can be accessed from the two personal computers. For example, when a file of the personal computer 501A is opened by an application of the personal computer 501B, the user selects the signal 502A using the operation switch 505, causes a picture of the personal computer 501A to be displayed, and moves or copies a desired file to the common folder. Thereafter, the user selects the signal 502B using the operation switch 505 and causes the monitor device 500 to display the screen of the personal computer 501B. Thereafter, the user opens the common folder, selects a desired file of the folder, and causes the application of the personal computer main body 501B to open the selected file. Thus, according to the related art, even if data is transferred between the personal computer 501A and the personal computer 501B, the process becomes troublesome.